Question: what is the start time for Aethelred the unready has position held  monarch of England?
Paraphrase: When did Aethrlred the Unread start his position as the Monarch of England?
SPARQL (Wikidata): SELECT ?value WHERE { wd:Q183499 p:P39 ?s . ?s ps:P39 wd:Q18810062 . ?s pq:P580 ?value}